Fig. 4.

Effect of commensal bacteria on zebrafish behavior. a Effect of lysates from ten different cultured bacteria on behavior of adult zebrafish, as indicated by probablity density function of speed before (blue) and after (green) application of the lysate. b–d Response of one fish to lysate from the bacteria Staphylococcus sp. ZWU0021. b Speed of the fish. The trace is color coded according to time, with dark gray indicating the delivery of the lysate. Position of the fish, before (c) and after (d) stimulus. Effect of bacterial lysate of adult fish, as indicated by time spent freezing (e), percentage of time at tank base (f), and time spent darting (g), as shown by Cumming estimation plots⁷². The raw data are plotted on the upper axes and each paired set of observations (before (Bef) and after (Aft) delivery of bacterial lysate) is connected by a line. On the lower axes, each paired mean difference is plotted as a bootstrap sampling distribution. Mean differences are depicted as dots; 95% confidence intervals are indicated by the ends of the vertical error bars